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2 lpwan S. Farrell, Ed.
3 Internet-Draft Trinity College Dublin
4 Intended status: Informational June 13, 2017
5 Expires: December 15, 2017
7 LPWAN Overview
8 draft-ietf-lpwan-overview-04
10 Abstract
12 Low Power Wide Area Networks (LPWAN) are wireless technologies with
13 characteristics such as large coverage areas, low bandwidth, possibly
14 very small packet and application layer data sizes and long battery
15 life operation. This memo is an informational overview of the set of
16 LPWAN technologies being considered in the IETF and of the gaps that
17 exist between the needs of those technologies and the goal of running
18 IP in LPWANs.
20 Status of This Memo
22 This Internet-Draft is submitted in full conformance with the
23 provisions of BCP 78 and BCP 79.
25 Internet-Drafts are working documents of the Internet Engineering
26 Task Force (IETF). Note that other groups may also distribute
27 working documents as Internet-Drafts. The list of current Internet-
28 Drafts is at http://datatracker.ietf.org/drafts/current/.
30 Internet-Drafts are draft documents valid for a maximum of six months
31 and may be updated, replaced, or obsoleted by other documents at any
32 time. It is inappropriate to use Internet-Drafts as reference
33 material or to cite them other than as "work in progress."
35 This Internet-Draft will expire on December 15, 2017.
37 Copyright Notice
39 Copyright (c) 2017 IETF Trust and the persons identified as the
40 document authors. All rights reserved.
42 This document is subject to BCP 78 and the IETF Trust's Legal
43 Provisions Relating to IETF Documents
44 (http://trustee.ietf.org/license-info) in effect on the date of
45 publication of this document. Please review these documents
46 carefully, as they describe your rights and restrictions with respect
47 to this document. Code Components extracted from this document must
48 include Simplified BSD License text as described in Section 4.e of
49 the Trust Legal Provisions and are provided without warranty as
50 described in the Simplified BSD License.
52 Table of Contents
54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
55 2. LPWAN Technologies . . . . . . . . . . . . . . . . . . . . . 3
56 2.1. LoRaWAN . . . . . . . . . . . . . . . . . . . . . . . . . 4
57 2.1.1. Provenance and Documents . . . . . . . . . . . . . . 4
58 2.1.2. Characteristics . . . . . . . . . . . . . . . . . . . 4
59 2.2. Narrowband IoT (NB-IoT) . . . . . . . . . . . . . . . . . 11
60 2.2.1. Provenance and Documents . . . . . . . . . . . . . . 11
61 2.2.2. Characteristics . . . . . . . . . . . . . . . . . . . 11
62 2.3. SIGFOX . . . . . . . . . . . . . . . . . . . . . . . . . 15
63 2.3.1. Provenance and Documents . . . . . . . . . . . . . . 16
64 2.3.2. Characteristics . . . . . . . . . . . . . . . . . . . 16
65 2.4. Wi-SUN Alliance Field Area Network (FAN) . . . . . . . . 20
66 2.4.1. Provenance and Documents . . . . . . . . . . . . . . 20
67 2.4.2. Characteristics . . . . . . . . . . . . . . . . . . . 21
68 3. Generic Terminology . . . . . . . . . . . . . . . . . . . . . 24
69 4. Gap Analysis . . . . . . . . . . . . . . . . . . . . . . . . 25
70 4.1. Naive application of IPv6 . . . . . . . . . . . . . . . . 25
71 4.2. 6LoWPAN . . . . . . . . . . . . . . . . . . . . . . . . . 26
72 4.2.1. Header Compression . . . . . . . . . . . . . . . . . 26
73 4.2.2. Address Autoconfiguration . . . . . . . . . . . . . . 27
74 4.2.3. Fragmentation . . . . . . . . . . . . . . . . . . . . 27
75 4.2.4. Neighbor Discovery . . . . . . . . . . . . . . . . . 28
76 4.3. 6lo . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
77 4.4. 6tisch . . . . . . . . . . . . . . . . . . . . . . . . . 29
78 4.5. RoHC . . . . . . . . . . . . . . . . . . . . . . . . . . 29
79 4.6. ROLL . . . . . . . . . . . . . . . . . . . . . . . . . . 29
80 4.7. CoAP . . . . . . . . . . . . . . . . . . . . . . . . . . 30
81 4.8. Mobility . . . . . . . . . . . . . . . . . . . . . . . . 30
82 4.9. DNS and LPWAN . . . . . . . . . . . . . . . . . . . . . . 30
83 5. Security Considerations . . . . . . . . . . . . . . . . . . . 31
84 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31
85 7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 32
86 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 34
87 9. Informative References . . . . . . . . . . . . . . . . . . . 35
88 Appendix A. Changes . . . . . . . . . . . . . . . . . . . . . . 40
89 A.1. From -00 to -01 . . . . . . . . . . . . . . . . . . . . . 40
90 A.2. From -01 to -02 . . . . . . . . . . . . . . . . . . . . . 40
91 A.3. From -02 to -03 . . . . . . . . . . . . . . . . . . . . . 40
92 A.4. From -03 to -04 . . . . . . . . . . . . . . . . . . . . . 41
93 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 41
95 1. Introduction
97 This document provides background material and an overview of the
98 technologies being considered in the IETF's Low Power Wide-Area
99 Networking (LPWAN) working group. We also provide a gap analysis
100 between the needs of these technologies and currently available IETF
101 specifications.
103 Most technologies in this space aim for similar goals of supporting
104 large numbers of very low-cost, low-throughput devices with very-low
105 power consumption, so that even battery-powered devices can be
106 deployed for years. LPWAN devices also tend to be constrained in
107 their use of bandwidth, for example with limited frequencies being
108 allowed to be used within limited duty-cycles (usually expressed as a
109 percentage of time per-hour that the device is allowed to transmit.)
110 And as the name implies, coverage of large areas is also a common
111 goal. So, by and large, the different technologies aim for
112 deployment in very similar circumstances.
114 Existing pilot deployments have shown huge potential and created much
115 industrial interest in these technologies. As of today, essentially
116 no LPWAN devices have IP capabilities. Connecting LPWANs to the
117 Internet would provide significant benefits to these networks in
118 terms of interoperability, application deployment, and management,
119 among others. The goal of the IETF LPWAN working group is to, where
120 necessary, adapt IETF-defined protocols, addressing schemes and
121 naming to this particular constrained environment.
123 This document is largely the work of the people listed in Section 7.
125 2. LPWAN Technologies
127 This section provides an overview of the set of LPWAN technologies
128 that are being considered in the LPWAN working group. The text for
129 each was mainly contributed by proponents of each technology.
131 Note that this text is not intended to be normative in any sense, but
132 simply to help the reader in finding the relevant layer 2
133 specifications and in understanding how those integrate with IETF-
134 defined technologies. Similarly, there is no attempt here to set out
135 the pros and cons of the relevant technologies.
137 Note that some of the technology-specific drafts referenced below may
138 have been updated since publication of this document.
140 2.1. LoRaWAN
142 Text here is largely from [I-D.farrell-lpwan-lora-overview]
144 2.1.1. Provenance and Documents
146 LoRaWAN is a wireless technology for long-range low-power low-data-
147 rate applications developed by the LoRa Alliance, a membership
148 consortium. This draft is based on
149 version 1.0.2 [LoRaSpec] of the LoRa specification. Version 1.0,
150 which has also seen some deployment, is available at [LoRaSpec1.0].
152 2.1.2. Characteristics
154 LoRaWAN networks are typically organized in a star-of-stars topology
155 in which gateways relay messages between end-devices and a central
156 "network server" in the backend. Gateways are connected to the
157 network server via IP links while end-devices use single-hop LoRaWAN
158 communication that can be received at one or more gateways. All
159 communication is generally bi-directional, although uplink
160 communication from end-devices to the network server are favored in
161 terms of overall bandwidth availability.
163 Figure 1 shows the entities involved in a LoRaWAN network.
165 +----------+
166 |End-device| * * *
167 +----------+ * +---------+
168 * | Gateway +---+
169 +----------+ * +---------+ | +---------+
170 |End-device| * * * +---+ Network +--- Application
171 +----------+ * | | Server |
172 * +---------+ | +---------+
173 +----------+ * | Gateway +---+
174 |End-device| * * * * +---------+
175 +----------+
176 Key: * LoRaWAN Radio
177 +---+ IP connectivity
179 Figure 1: LoRaWAN architecture
181 o End-device: a LoRa client device, sometimes called a mote.
182 Communicates with gateways.
184 o Gateway: a radio on the infrastructure-side, sometimes called a
185 concentrator or base-station. Communicates with end-devices and,
186 via IP, with a network server.
188 o Network Server: The Network Server (NS) terminates the LoRaWAN MAC
189 layer for the end-devices connected to the network. It is the
190 center of the star topology.
192 o Uplink message: refers to communications from end-device to
193 network server or application via one or more gateways.
195 o Downlink message: refers to communications from network server or
196 application via one gateway to a single end-device or a group of
197 end-devices (considering multicasting).
199 o Application: refers to application layer code both on the end-
200 device and running "behind" the network server. For LoRaWAN,
201 there will generally only be one application running on most end-
202 devices. Interfaces between the network server and application
203 are not further described here.
205 In LoRaWAN networks, end-device transmissions may be received at
206 multiple gateways, so during nominal operation a network server may
207 see multiple instances of the same uplink message from an end-device.
209 The LoRaWAN network infrastructure manages the data rate and RF
210 output power for each end-device individually by means of an adaptive
211 data rate (ADR) scheme. End-devices may transmit on any channel
212 allowed by local regulation at any time.
214 LoRaWAN radios make use of industrial, scientific and medical (ISM)
215 bands, for example, 433MHz and 868MHz within the European Union and
216 915MHz in the Americas.
218 The end-device changes channel in a pseudo-random fashion for every
219 transmission to help make the system more robust to interference and/
220 or to conform to local regulations.
222 Figure 2 below shows that after a transmission slot a Class A device
223 turns on its receiver for two short receive windows that are offset
224 from the end of the transmission window. End-devices can only
225 transmit a subsequent uplink frame after the end of the associated
226 receive windows. When a device joins a LoRaWAN network, there are
227 similar timeouts on parts of that process.
229 |----------------------------| |--------| |--------|
230 | Tx | | Rx | | Rx |
231 |----------------------------| |--------| |--------|
232 |---------|
233 Rx delay 1
234 |------------------------|
235 Rx delay 2
237 Figure 2: LoRaWAN Class A transmission and reception window
239 Given the different regional requirements the detailed specification
240 for the LoRaWAN physical layer (taking up more than 30 pages of the
241 specification) is not reproduced here. Instead and mainly to
242 illustrate the kinds of issue encountered, in Table 1 we present some
243 of the default settings for one ISM band (without fully explaining
244 those here) and in Table 2 we describe maxima and minima for some
245 parameters of interest to those defining ways to use IETF protocols
246 over the LoRaWAN MAC layer.
248 +------------------------+------------------------------------------+
249 | Parameters | Default Value |
250 +------------------------+------------------------------------------+
251 | Rx delay 1 | 1 s |
252 | | |
253 | Rx delay 2 | 2 s (must be RECEIVE_DELAY1 + 1s) |
254 | | |
255 | join delay 1 | 5 s |
256 | | |
257 | join delay 2 | 6 s |
258 | | |
259 | 868MHz Default | 3 (868.1,868.2,868.3), data rate: 0.3-5 |
260 | channels | kbps |
261 +------------------------+------------------------------------------+
263 Table 1: Default settings for EU868MHz band
265 +-----------------------------------------------+--------+----------+
266 | Parameter/Notes | Min | Max |
267 +-----------------------------------------------+--------+----------+
268 | Duty Cycle: some but not all ISM bands impose | 1% | no-limit |
269 | a limit in terms of how often an end-device | | |
270 | can transmit. In some cases LoRaWAN is more | | |
271 | stringent in an attempt to avoid congestion. | | |
272 | | | |
273 | EU 868MHz band data rate/frame-size | 250 | 50000 |
274 | | bits/s | bits/s : |
275 | | : 59 | 250 |
276 | | octets | octets |
277 | | | |
278 | US 915MHz band data rate/frame-size | 980 | 21900 |
279 | | bits/s | bits/s : |
280 | | : 19 | 250 |
281 | | octets | octets |
282 +-----------------------------------------------+--------+----------+
284 Table 2: Minima and Maxima for various LoRaWAN Parameters
286 Note that in the case of the smallest frame size (19 octets), 8
287 octets are required for LoRa MAC layer headers leaving only 11 octets
288 for payload (including MAC layer options). However, those settings
289 do not apply for the join procedure - end-devices are required to use
290 a channel and data rate that can send the 23-byte Join-request
291 message for the join procedure.
293 Uplink and downlink higher layer data is carried in a MACPayload.
294 There is a concept of "ports" (an optional 8-bit value) to handle
295 different applications on an end-device. Port zero is reserved for
296 LoRaWAN specific messaging, such as the configuration of the end
297 device's network parameters (available channels, data rates, ADR
298 parameters, RX1/2 delay, etc.).
300 In addition to carrying higher layer PDUs there are Join-Request and
301 Join-Response (aka Join-Accept) messages for handling network access.
302 And so-called "MAC commands" (see below) up to 15 bytes long can be
303 piggybacked in an options field ("FOpts").
305 There are a number of MAC commands for link and device status
306 checking, ADR and duty-cycle negotiation, managing the RX windows and
307 radio channel settings. For example, the link check response message
308 allows the network server (in response to a request from an end-
309 device) to inform an end-device about the signal attenuation seen
310 most recently at a gateway, and to also tell the end-device how many
311 gateways received the corresponding link request MAC command.
313 Some MAC commands are initiated by the network server. For example,
314 one command allows the network server to ask an end-device to reduce
315 its duty-cycle to only use a proportion of the maximum allowed in a
316 region. Another allows the network server to query the end-device's
317 power status with the response from the end-device specifying whether
318 it has an external power source or is battery powered (in which case
319 a relative battery level is also sent to the network server).
321 A LoRaWAN network has a network identifier ("NwkID"), currently a
322 seven-bit value. A private network (common for LoRaWAN) can use the
323 value zero or one. If a network wishes to support "foreign" end-
324 devices then the NwkID needs to be registered with the LoRA Alliance,
325 in which case the NwkID is the seven least significant bits of a
326 registered 24-bit NetID. (Note however, that the methods for
327 "roaming" are defined in the upcoming LoRaWAN 1.1 specification.)
329 In order to operate nominally on a LoRaWAN network, a device needs a
330 32-bit device address, which is the catenation of the NwkID and a
331 25-bit device-specific network address that is assigned when the
332 device "joins" the network (see below for the join procedure) or that
333 is pre-provisioned into the device.
335 End-devices are assumed to work with one or a quite limited number of
336 applications, identified by a 64-bit AppEUI, which is assumed to be a
337 registered IEEE EUI64 value. In addition, a device needs to have two
338 symmetric session keys, one for protecting network artifacts
339 (port=0), the NwkSKey, and another for protecting application layer
340 traffic, the AppSKey. Both keys are used for 128-bit AES
341 cryptographic operations. So, one option is for an end-device to
342 have all of the above, plus channel information, somehow
343 (pre-)provisioned, in which case the end-device can simply start
344 transmitting. This is achievable in many cases via out-of-band means
345 given the nature of LoRaWAN networks. Table 3 summarizes these
346 values.
348 +---------+---------------------------------------------------------+
349 | Value | Description |
350 +---------+---------------------------------------------------------+
351 | DevAddr | DevAddr (32-bits) = device-specific network address |
352 | | generated from the NwkID |
353 | | |
354 | AppEUI | IEEE EUI64 naming the application |
355 | | |
356 | NwkSKey | 128-bit network session key for use with AES |
357 | | |
358 | AppSKey | 128-bit application session key for use with AES |
359 +---------+---------------------------------------------------------+
361 Table 3: Values required for nominal operation
363 As an alternative, end-devices can use the LoRaWAN join procedure in
364 order to setup some of these values and dynamically gain access to
365 the network. To use the join procedure, an end-device must still
366 know the AppEUI, and in addition, a different (long-term) symmetric
367 key that is bound to the AppEUI - this is the application key
368 (AppKey), and is distinct from the application session key (AppSKey).
369 The AppKey is required to be specific to the device, that is, each
370 end-device should have a different AppKey value. And finally, the
371 end-device also needs a long-term identifier for itself,
372 syntactically also an EUI-64, and known as the device EUI or DevEUI.
373 Table 4 summarizes these values.
375 +---------+----------------------------------------------------+
376 | Value | Description |
377 +---------+----------------------------------------------------+
378 | DevEUI | IEEE EUI64 naming the device |
379 | | |
380 | AppEUI | IEEE EUI64 naming the application |
381 | | |
382 | AppKey | 128-bit long term application key for use with AES |
383 +---------+----------------------------------------------------+
385 Table 4: Values required for join procedure
387 The join procedure involves a special exchange where the end-device
388 asserts the AppEUI and DevEUI (integrity protected with the long-term
389 AppKey, but not encrypted) in a Join-request uplink message. This is
390 then routed to the network server which interacts with an entity that
391 knows that AppKey to verify the Join-request. All going well, a
392 Join-accept downlink message is returned from the network server to
393 the end-device that specifies the 24-bit NetID, 32-bit DevAddr and
394 channel information and from which the AppSKey and NwkSKey can be
395 derived based on knowledge of the AppKey. This provides the end-
396 device with all the values listed in Table 3.
398 All payloads are encrypted and have data integrity. MAC commands,
399 when sent as a payload (port zero), are therefore protected. MAC
400 commands piggy-backed as frame options ("FOpts") are however sent in
401 clear. Any MAC commands sent as frame options and not only as
402 payload, are visible to a passive attacker but are not malleable for
403 an active attacker due to the use of the Message Integrity Check
404 (MIC) described below..
406 For LoRaWAN version 1.0.x, the NWkSkey session key is used to provide
407 data integrity between the end-device and the network server. The
408 AppSKey is used to provide data confidentiality between the end-
409 device and network server, or to the application "behind" the network
410 server, depending on the implementation of the network.
412 All MAC layer messages have an outer 32-bit MIC calculated using AES-
413 CMAC calculated over the ciphertext payload and other headers and
414 using the NwkSkey. Payloads are encrypted using AES-128, with a
415 counter-mode derived from IEEE 802.15.4 using the AppSKey. Gateways
416 are not expected to be provided with the AppSKey or NwkSKey, all of
417 the infrastructure-side cryptography happens in (or "behind") the
418 network server. When session keys are derived from the AppKey as a
419 result of the join procedure the Join-accept message payload is
420 specially handled.
422 The long-term AppKey is directly used to protect the Join-accept
423 message content, but the function used is not an AES-encrypt
424 operation, but rather an AES-decrypt operation. The justification is
425 that this means that the end-device only needs to implement the AES-
426 encrypt operation. (The counter mode variant used for payload
427 decryption means the end-device doesn't need an AES-decrypt
428 primitive.)
430 The Join-accept plaintext is always less than 16 bytes long, so
431 electronic code book (ECB) mode is used for protecting Join-accept
432 messages. The Join-accept contains an AppNonce (a 24 bit value) that
433 is recovered on the end-device along with the other Join-accept
434 content (e.g. DevAddr) using the AEs-encrypt operation. Once the
435 Join-accept payload is available to the end-device the session keys
436 are derived from the AppKey, AppNonce and other values, again using
437 an ECB mode AES-encrypt operation, with the plaintext input being a
438 maximum of 16 octets.
440 2.2. Narrowband IoT (NB-IoT)
442 Text here is largely from [I-D.ratilainen-lpwan-nb-iot]
444 2.2.1. Provenance and Documents
446 Narrowband Internet of Things (NB-IoT) is developed and standardized
447 by 3GPP. The standardization of NB-IoT was finalized with 3GPP
448 Release 13 in June 2016, and further enhancements for NB-IoT are
449 specified in 3GPP Release 14 in 2017, for example in the form of
450 multicast support. Further features and improvements will be
451 developed in the following releases, but NB-IoT has been ready to be
452 deployed since 2016, and is rather simple to deploy especially in the
453 existing LTE networks with a software upgrade in the operator's base
454 stations. For more information of what has been specified for NB-
455 IoT, 3GPP specification 36.300 [TGPP36300] provides an overview and
456 overall description of the E-UTRAN radio interface protocol
457 architecture, while specifications 36.321 [TGPP36321], 36.322
458 [TGPP36322], 36.323 [TGPP36323] and 36.331 [TGPP36331] give more
459 detailed description of MAC, RLC, PDCP and RRC protocol layers,
460 respectively. Note that the description below assumes familiarity
461 with numerous 3GPP terms.
463 2.2.2. Characteristics
465 Specific targets for NB-IoT include: Less than US$5 module cost,
466 extended coverage of 164 dB maximum coupling loss, battery life of
467 over 10 years, ~55000 devices per cell and uplink reporting latency
468 of less than 10 seconds.
470 NB-IoT supports Half Duplex FDD operation mode with 60 kbps peak rate
471 in uplink and 30 kbps peak rate in downlink, and a maximum
472 transmission unit (MTU) size of 1600 bytes limited by PDCP layer (see
473 Figure 4 for the protocol structure), which is the highest layer in
474 the user plane, as explained later. Any packet size up to the said
475 MTU size can be passed to the NB-IoT stack from higher layers,
476 segmentation of the packet is performed in the RLC layer, which can
477 segment the data to transmission blocks with size as small as 16
478 bits. As the name suggests, NB-IoT uses narrowbands with the
479 bandwidth of 180 kHz in both downlink and uplink. The multiple
480 access scheme used in the downlink is OFDMA with 15 kHz sub-carrier
481 spacing. In uplink SC-FDMA single tone with either 15kHz or 3.75 kHz
482 tone spacing is used, or optionally multi-tone SC- FDMA can be used
483 with 15 kHz tone spacing.
485 NB-IoT can be deployed in three ways. In-band deployment means that
486 the narrowband is deployed inside the LTE band and radio resources
487 are flexibly shared between NB-IoT and normal LTE carrier. In Guard-
488 band deployment the narrowband uses the unused resource blocks
489 between two adjacent LTE carriers. Standalone deployment is also
490 supported, where the narrowband can be located alone in dedicated
491 spectrum, which makes it possible for example to reframe a GSM
492 carrier at 850/900 MHz for NB-IoT. All three deployment modes are
493 used in licensed frequency bands. The maximum transmission power is
494 either 20 or 23 dBm for uplink transmissions, while for downlink
495 transmission the eNodeB may use higher transmission power, up to 46
496 dBm depending on the deployment.
498 A maximum coupling loss (MCL) target for NB-IoT coverage enhancements
499 defined by 3GPP is 164 dB. With this MCL, the performance of NB-IoT
500 in downlink varies between 200 bps and 2-3 kbps, depending on the
501 deployment mode. Stand-alone operation may achieve the highest data
502 rates, up to few kbps, while in-band and guard-band operations may
503 reach several hundreds of bps. NB-IoT may even operate with MCL
504 higher than 170 dB with very low bit rates.
506 For signaling optimization, two options are introduced in addition to
507 legacy LTE RRC connection setup; mandatory Data-over-NAS (Control
508 Plane optimization, solution 2 in [TGPP23720]) and optional RRC
509 Suspend/Resume (User Plane optimization, solution 18 in [TGPP23720]).
510 In the control plane optimization the data is sent over Non-Access
511 Stratum, directly to/from Mobility Management Entity (MME) (see
512 Figure 3 for the network architecture) in the core network to the
513 User Equipment (UE) without interaction from the base station. This
514 means there are no Access Stratum security or header compression
515 provided by the PDCP layer in the eNodeB, as the Access Stratum is
516 bypassed, and only limited RRC procedures. RoHC based header
517 compression may still optionally be provided and terminated in MME.
519 The RRC Suspend/Resume procedures reduce the signaling overhead
520 required for UE state transition from RRC Idle to RRC Connected mode
521 compared to legacy LTE operation in order to have quicker user plane
522 transaction with the network and return to RRC Idle mode faster.
524 In order to prolong device battery life, both power-saving mode (PSM)
525 and extended DRX (eDRX) are available to NB-IoT. With eDRX the RRC
526 Connected mode DRX cycle is up to 10.24 seconds and in RRC Idle the
527 eDRX cycle can be up to 3 hours. In PSM the device is in a deep
528 sleep state and only wakes up for uplink reporting, after which there
529 is a window, configured by the network, during which the device
530 receiver is open for downlink connectivity, of for periodical "keep-
531 alive" signaling (PSM uses periodic TAU signaling with additional
532 reception window for downlink reachability).
534 Since NB-IoT operates in licensed spectrum, it has no channel access
535 restrictions allowing up to a 100% duty-cycle.
537 3GPP access security is specified in [TGPP33203].
539 +--+
540 |UE| \ +------+ +------+
541 +--+ \ | MME |------| HSS |
542 \ / +------+ +------+
543 +--+ \+-----+ / |
544 |UE| ----| eNB |- |
545 +--+ /+-----+ \ |
546 / \ +--------+
547 / \| | +------+ Service PDN
548 +--+ / | S-GW |----| P-GW |---- e.g. Internet
549 |UE| | | +------+
550 +--+ +--------+
552 Figure 3: 3GPP network architecture
554 Figure 3 shows the 3GPP network architecture, which applies to NB-
555 IoT. Mobility Management Entity (MME) is responsible for handling
556 the mobility of the UE. MME tasks include tracking and paging UEs,
557 session management, choosing the Serving gateway for the UE during
558 initial attachment and authenticating the user. At MME, the Non-
559 Access Stratum (NAS) signaling from the UE is terminated.
561 Serving Gateway (S-GW) routes and forwards the user data packets
562 through the access network and acts as a mobility anchor for UEs
563 during handover between base stations known as eNodeBs and also
564 during handovers between NB-IoT and other 3GPP technologies.
566 Packet Data Node Gateway (P-GW) works as an interface between 3GPP
567 network and external networks.
569 The Home Subscriber Server (HSS) contains user-related and
570 subscription- related information. It is a database, which performs
571 mobility management, session establishment support, user
572 authentication and access authorization.
574 E-UTRAN consists of components of a single type, eNodeB. eNodeB is a
575 base station, which controls the UEs in one or several cells.
577 The illustration of 3GPP radio protocol architecture can be seen from
578 Figure 4.
580 +---------+ +---------+
581 | NAS |----|-----------------------------|----| NAS |
582 +---------+ | +---------+---------+ | +---------+
583 | RRC |----|----| RRC | S1-AP |----|----| S1-AP |
584 +---------+ | +---------+---------+ | +---------+
585 | PDCP |----|----| PDCP | SCTP |----|----| SCTP |
586 +---------+ | +---------+---------+ | +---------+
587 | RLC |----|----| RLC | IP |----|----| IP |
588 +---------+ | +---------+---------+ | +---------+
589 | MAC |----|----| MAC | L2 |----|----| L2 |
590 +---------+ | +---------+---------+ | +---------+
591 | PHY |----|----| PHY | PHY |----|----| PHY |
592 +---------+ +---------+---------+ +---------+
593 LTE-Uu S1-MME
594 UE eNodeB MME
596 Figure 4: 3GPP radio protocol architecture for control plane
598 Control plane protocol stack
600 The radio protocol architecture of NB-IoT (and LTE) is separated into
601 control plane and user plane. The control plane consists of
602 protocols which control the radio access bearers and the connection
603 between the UE and the network. The highest layer of control plane
604 is called Non-Access Stratum (NAS), which conveys the radio signaling
605 between the UE and the EPC, passing transparently through the radio
606 network. It is responsible for authentication, security control,
607 mobility management and bearer management.
609 Access Stratum (AS) is the functional layer below NAS, and in control
610 plane it consists of Radio Resource Control protocol (RRC)
611 [TGPP36331], which handles connection establishment and release
612 functions, broadcast of system information, radio bearer
613 establishment, reconfiguration and release. RRC configures the user
614 and control planes according to the network status. There exists two
615 RRC states, RRC_Idle or RRC_Connected, and RRC entity controls the
616 switching between these states. In RRC_Idle, the network knows that
617 the UE is present in the network and the UE can be reached in case of
618 incoming call/downlink data. In this state, the UE monitors paging,
619 performs cell measurements and cell selection and acquires system
620 information. Also the UE can receive broadcast and multicast data,
621 but it is not expected to transmit or receive unicast data. In
622 RRC_Connected the UE has a connection to the eNodeB, the network
623 knows the UE location on the cell level and the UE may receive and
624 transmit unicast data. An RRC connection is established when the UE
625 is expected to be active in the network, to transmit or receive data.
626 The RRC connection is released, switching back to RRC_Idle, when
627 there is no more traffic in order to preserve UE battery life and
628 radio resources. However, a new feature was introduced for NB-IoT,
629 as mentioned earlier, which allows data to be transmitted from the
630 MME directly to the UE transparently to the eNodeB, thus bypassing AS
631 functions.
633 Packet Data Convergence Protocol's (PDCP) [TGPP36323] main services
634 in control plane are transfer of control plane data, ciphering and
635 integrity protection.
637 Radio Link Control protocol (RLC) [TGPP36322] performs transfer of
638 upper layer PDUs and optionally error correction with Automatic
639 Repeat reQuest (ARQ), concatenation, segmentation, and reassembly of
640 RLC SDUs, in-sequence delivery of upper layer PDUs, duplicate
641 detection, RLC SDU discard, RLC-re-establishment and protocol error
642 detection and recovery.
644 Medium Access Control protocol (MAC) [TGPP36321] provides mapping
645 between logical channels and transport channels, multiplexing of MAC
646 SDUs, scheduling information reporting, error correction with HARQ,
647 priority handling and transport format selection.
649 Physical layer [TGPP36201] provides data transport services to higher
650 layers. These include error detection and indication to higher
651 layers, FEC encoding, HARQ soft-combining. Rate matching and mapping
652 of the transport channels onto physical channels, power weighting and
653 modulation of physical channels, frequency and time synchronization
654 and radio characteristics measurements.
656 User plane protocol stack
658 User plane is responsible for transferring the user data through the
659 Access Stratum. It interfaces with IP and the highest layer of user
660 plane is PDCP, which in user plane performs header compression using
661 Robust Header Compression (RoHC), transfer of user plane data between
662 eNodeB and UE, ciphering and integrity protection. Similar to
663 control plane, lower layers in user plane include RLC, MAC and
664 physical layer performing the same tasks as in control plane.
666 2.3. SIGFOX
668 Text here is largely from
669 [I-D.zuniga-lpwan-sigfox-system-description] which may have been
670 updated since this was published.
672 2.3.1. Provenance and Documents
674 The SIGFOX LPWAN is in line with the terminology and specifications
675 being defined by ETSI [etsi_unb]. As of today, SIGFOX's network has
676 been fully deployed in 12 countries, with ongoing deployments on 26
677 other countries, giving in total a geography of 2 million square
678 kilometers, containing 512 million people.
680 2.3.2. Characteristics
682 SIGFOX LPWAN autonomous battery-operated devices send only a few
683 bytes per day, week or month, in principle allowing them to remain on
684 a single battery for up to 10-15 years. Hence, the system is
685 designed as to allow devices to last several years, sometimes even
686 buried underground.
688 Since the radio protocol is connection-less and optimized for uplink
689 communications, the capacity of a SIGFOX base station depends on the
690 number of messages generated by devices, and not on the actual number
691 of devices. Likewise, the battery life of devices depends on the
692 number of messages generated by the device. Depending on the use
693 case, devices can vary from sending less than one message per device
694 per day, to dozens of messages per device per day.
696 The coverage of the cell depends on the link budget and on the type
697 of deployment (urban, rural, etc.). The radio interface is compliant
698 with the following regulations:
700 Spectrum allocation in the USA [fcc_ref]
702 Spectrum allocation in Europe [etsi_ref]
704 Spectrum allocation in Japan [arib_ref]
706 The SIGFOX radio interface is also compliant with the local
707 regulations of the following countries: Australia, Brazil, Canada,
708 Kenya, Lebanon, Mauritius, Mexico, New Zealand, Oman, Peru,
709 Singapore, South Africa, South Korea, and Thailand.
711 The radio interface is based on Ultra Narrow Band (UNB)
712 communications, which allow an increased transmission range by
713 spending a limited amount of energy at the device. Moreover, UNB
714 allows a large number of devices to coexist in a given cell without
715 significantly increasing the spectrum interference.
717 Both uplink and downlink are supported, although the system is
718 optimized for uplink communications. Due to spectrum optimizations,
719 different uplink and downlink frames and time synchronization methods
720 are needed.
722 The main radio characteristics of the UNB uplink transmission are:
724 o Channelization mask: 100 Hz / 600 Hz (depending on the region)
726 o Uplink baud rate: 100 baud / 600 baud (depending on the region)
728 o Modulation scheme: DBPSK
730 o Uplink transmission power: compliant with local regulation
732 o Link budget: 155 dB (or better)
734 o Central frequency accuracy: not relevant, provided there is no
735 significant frequency drift within an uplink packet transmission
737 For example, in Europe the UNB uplink frequency band is limited to
738 868.00 to 868.60 MHz, with a maximum output power of 25 mW and a duty
739 cycle of 1%.
741 The format of the uplink frame is the following:
743 +--------+--------+--------+------------------+-------------+-----+
744 |Preamble| Frame | Dev ID | Payload |Msg Auth Code| FCS |
745 | | Sync | | | | |
746 +--------+--------+--------+------------------+-------------+-----+
748 Figure 5: Uplink Frame Format
750 The uplink frame is composed of the following fields:
752 o Preamble: 19 bits
754 o Frame sync and header: 29 bits
756 o Device ID: 32 bits
758 o Payload: 0-96 bits
760 o Authentication: 16-40 bits
762 o Frame check sequence: 16 bits (CRC)
764 The main radio characteristics of the UNB downlink transmission are:
766 o Channelization mask: 1.5 kHz
768 o Downlink baud rate: 600 baud
770 o Modulation scheme: GFSK
772 o Downlink transmission power: 500 mW / 4W (depending on the region)
774 o Link budget: 153 dB (or better)
776 o Central frequency accuracy: Centre frequency of downlink
777 transmission are set by the network according to the corresponding
778 uplink transmission
780 For example, in Europe the UNB downlink frequency band is limited to
781 869.40 to 869.65 MHz, with a maximum output power of 500 mW with 10%
782 duty cycle.
784 The format of the downlink frame is the following:
786 +------------+-----+---------+------------------+-------------+-----+
787 | Preamble |Frame| ECC | Payload |Msg Auth Code| FCS |
788 | |Sync | | | | |
789 +------------+-----+---------+------------------+-------------+-----+
791 Figure 6: Downlink Frame Format
793 The downlink frame is composed of the following fields:
795 o Preamble: 91 bits
797 o Frame sync and header: 13 bits
799 o Error Correcting Code (ECC): 32 bits
801 o Payload: 0-64 bits
803 o Authentication: 16 bits
805 o Frame check sequence: 8 bits (CRC)
807 The radio interface is optimized for uplink transmissions, which are
808 asynchronous. Downlink communications are achieved by devices
809 querying the network for available data.
811 A device willing to receive downlink messages opens a fixed window
812 for reception after sending an uplink transmission. The delay and
813 duration of this window have fixed values. The network transmits the
814 downlink message for a given device during the reception window, and
815 the network also selects the base station (BS) for transmitting the
816 corresponding downlink message.
818 Uplink and downlink transmissions are unbalanced due to the
819 regulatory constraints on ISM bands. Under the strictest
820 regulations, the system can allow a maximum of 140 uplink messages
821 and 4 downlink messages per device per day. These restrictions can
822 be slightly relaxed depending on system conditions and the specific
823 regulatory domain of operation.
825 +---+
826 |DEV| * +------+
827 +---+ * | RA |
828 * +------+
829 +---+ * |
830 |DEV| * * * * |
831 +---+ * +----+ |
832 * | BS | \ +--------+
833 +---+ * +----+ \ | |
834 DA -----|DEV| * * * | SC |----- NA
835 +---+ * / | |
836 * +----+ / +--------+
837 +---+ * | BS |/
838 |DEV| * * * * +----+
839 +---+ *
840 *
841 +---+ *
842 |DEV| * *
843 +---+
845 Figure 7: SIGFOX network architecture
847 Figure 7 depicts the different elements of the SIGFOX network
848 architecture.
850 SIGFOX has a "one-contract one-network" model allowing devices to
851 connect in any country, without any need or notion of either roaming
852 or handover.
854 The architecture consists of a single cloud-based core network, which
855 allows global connectivity with minimal impact on the end device and
856 radio access network. The core network elements are the Service
857 Center (SC) and the Registration Authority (RA). The SC is in charge
858 of the data connectivity between the Base Station (BS) and the
859 Internet, as well as the control and management of the BSs and End
860 Points. The RA is in charge of the End Point network access
861 authorization.
863 The radio access network is comprised of several BSs connected
864 directly to the SC. Each BS performs complex L1/L2 functions,
865 leaving some L2 and L3 functionalities to the SC.
867 The Devices (DEVs) or End Points (EPs) are the objects that
868 communicate application data between local device applications (DAs)
869 and network applications (NAs).
871 Devices (or EPs) can be static or nomadic, as they associate with the
872 SC and they do not attach to any specific BS. Hence, they can
873 communicate with the SC through one or multiple BSs.
875 Due to constraints in the complexity of the Device, it is assumed
876 that Devices host only one or very few device applications, which
877 most of the time communicate each to a single network application at
878 a time.
880 The radio protocol provides mechanisms to authenticate and ensure
881 integrity of the message. This is achieved by using a unique device
882 ID and a message authentication code, which allow ensuring that the
883 message has been generated and sent by the device with the ID claimed
884 in the message.
886 Security keys are independent for each device. These keys are
887 associated with the device ID and they are pre-provisioned.
888 Application data can be encrypted at the application level or not,
889 depending on the criticality of the use case, allowing hence to
890 balance cost and effort vs. risk.
892 2.4. Wi-SUN Alliance Field Area Network (FAN)
894 Text here is via personal communication from Bob Heile
895 (bheile@ieee.org) and was authored by Bob and Sum Chin Sean. Duffy
896 (paduffy@cisco.com) also provided additional comments/input on this
897 section.
899 2.4.1. Provenance and Documents
901 The Wi-SUN Alliance is an industry alliance
902 for smart city, smart grid, smart utility, and a broad set of general
903 IoT applications. The Wi-SUN Alliance Field Area Network (FAN)
904 profile is open standards based (primarily on IETF and IEEE802
905 standards) and was developed to address applications like smart
906 municipality/city infrastructure monitoring and management, electric
907 vehicle (EV) infrastructure, advanced metering infrastructure (AMI),
908 distribution automation (DA), supervisory control and data
909 acquisition (SCADA) protection/management, distributed generation
910 monitoring and management, and many more IoT applications.
911 Additionally, the Alliance has created a certification program to
912 promote global multi-vendor interoperability.
914 The FAN profile is currently being specified within ANSI/TIA as an
915 extension of work previously done on Smart Utility Networks.
916 [ANSI-4957-000]. Updates to those specifications intended to be
917 published in 2017 will contain details of the FAN profile. A current
918 snapshot of the work to produce that profile is presented in
919 [wisun-pressie1] [wisun-pressie2] .
921 2.4.2. Characteristics
923 The FAN profile is an IPv6 frequency hopping wireless mesh network
924 with support for enterprise level security. The frequency hopping
925 wireless mesh topology aims to offer superior network robustness,
926 reliability due to high redundancy, good scalability due to the
927 flexible mesh configuration and good resilience to interference.
928 Very low power modes are in development permitting long term battery
929 operation of network nodes.
931 The core architecture of Wi-SUN FAN is a mesh network. A FAN
932 contains one or more networks. Within a network, nodes assume one of
933 three operational roles. First, each network contains a Border
934 Router providing Wide Area Network (WAN) connectivity to the network.
935 The Border Router maintains source routing tables for all nodes
936 within its network, provides node authentication and key management
937 services, and disseminates network-wide information such as broadcast
938 schedules. Secondly, Router nodes, which provide upward and downward
939 packet forwarding (within a network). A Router also provides
940 services for relaying security and address management protocols.
941 Lastly, Leaf nodes provide minimum capabilities: discovering and
942 joining a network, send/receive IPv6 packets, etc. A low power
943 network may contain a mesh topology with Routers at the edges that
944 construct a star topology with Leaf nodes.
946 The FAN profile is based on various open standards developed by the
947 IETF (including [RFC0768], [RFC2460], [RFC4443] and [RFC6282]),
948 IEEE802 (including [IEEE-802-15-4] and [IEEE-802-15-9]) and ANSI/TIA
949 [ANSI-4957-210] for low power and lossy networks.
951 The FAN profile specification provides an application-independent
952 IPv6-based transport service for both connectionless (i.e. UDP) and
953 connection-oriented (i.e. TCP) services. There are two possible
954 methods for establishing the IPv6 packet routing: mandatory Routing
955 Protocol for Low-Power and Lossy Networks (RPL) at the Network layer
956 or optional Multi-Hop Delivery Service (MHDS) at the Data Link layer.
957 Table 5 provides an overview of the FAN network stack.
959 The Transport service is based on User Datagram Protocol (UDP)
960 defined in RFC768 or Transmission Control Protocol (TCP) defined in
961 RFC793.
963 The Network service is provided by IPv6 defined in RFC2460 with
964 6LoWPAN adaptation as defined in RC4944 and RFC6282. Additionally,
965 ICMPv6, as defined in RFC4443, is used for control plane in
966 information exchange.
968 The Data Link service provides both control/management of the
969 Physical layer and data transfer/management services to the Network
970 layer. These services are divided into Media Access Control (MAC)
971 and Logical Link Control (LLC) sub-layers. The LLC sub-layer
972 provides a protocol dispatch service which supports 6LoWPAN and an
973 optional MAC sub-layer mesh service. The MAC sub-layer is
974 constructed using data structures defined in IEEE802.15.4-2015.
975 Multiple modes of frequency hopping are defined. The entire MAC
976 payload is encapsulated in an IEEE802.15.9 Information Element to
977 enable LLC protocol dispatch between upper layer 6LoWPAN processing,
978 MAC sublayer mesh processing, etc. These areas will be expanded once
979 IEEE802.15.12 is completed
981 The PHY service is derived from a sub-set of the SUN FSK
982 specification in IEEE802.15.4-2015. The 2-FSK modulation schemes,
983 with channel spacing range from 200 to 600 kHz, are defined to
984 provide data rates from 50 to 300 kbps, with Forward Error Coding
985 (FEC) as an optional feature. Towards enabling ultra-low-power
986 applications, the PHY layer design is also extendable to low energy
987 and critical infrastructure monitoring networks.
989 +------------------------------+------------------------------------+
990 | Layer | Description |
991 +------------------------------+------------------------------------+
992 | IPv6 protocol suite | TCP/UDP |
993 | | |
994 | | 6LoWPAN Adaptation + Header |
995 | | Compression |
996 | | |
997 | | DHCPv6 for IP address management. |
998 | | |
999 | | Routing using RPL. |
1000 | | |
1001 | | ICMPv6. |
1002 | | |
1003 | | Unicast and Multicast forwarding. |
1004 | | |
1005 | MAC based on IEEE 802.15.4e | Frequency hopping |
1006 | + IE extensions | |
1007 | | |
1008 | | Discovery and Join |
1009 | | |
1010 | | Protocol Dispatch (IEEE 802.15.9) |
1011 | | |
1012 | | Several Frame Exchange patterns |
1013 | | |
1014 | | Optional Mesh Under routing (ANSI |
1015 | | 4957.210). |
1016 | | |
1017 | PHY based on 802.15.4g | Various data rates and regions |
1018 | | |
1019 | Security | 802.1X/EAP-TLS/PKI |
1020 | | Authentication. |
1021 | | |
1022 | | 802.11i Group Key Management |
1023 | | |
1024 | | Optional ETSI-TS-102-887-2 Node 2 |
1025 | | Node Key Management |
1026 +------------------------------+------------------------------------+
1028 Table 5: Wi-SUN Stack Overview
1030 The FAN security supports Data Link layer network access control,
1031 mutual authentication, and establishment of a secure pairwise link
1032 between a FAN node and its Border Router, which is implemented with
1033 an adaptation of IEEE802.1X and EAP-TLS as described in [RFC5216]
1034 using secure device identity as described in IEEE802.1AR.
1035 Certificate formats are based upon [RFC5280]. A secure group link
1036 between a Border Router and a set of FAN nodes is established using
1037 an adaptation of the IEEE802.11 Four-Way Handshake. A set of 4 group
1038 keys are maintained within the network, one of which is the current
1039 transmit key. Secure node to node links are supported between one-
1040 hop FAN neighbors using an adaptation of ETSI-TS-102-887-2. FAN
1041 nodes implement Frame Security as specified in IEEE802.15.4-2015.
1043 3. Generic Terminology
1045 LPWAN technologies, such as those discussed above, have similar
1046 architectures but different terminology. We can identify different
1047 types of entities in a typical LPWAN network:
1049 o End-Devices are the devices or the "things" (e.g. sensors,
1050 actuators, etc.), they are named differently in each technology
1051 (End Device, User Equipment or End Point). There can be a high
1052 density of end devices per radio gateway.
1054 o The Radio Gateway, which is the end point of the constrained link.
1055 It is known as: Gateway, Evolved Node B or Base station.
1057 o The Network Gateway or Router is the interconnection node between
1058 the Radio Gateway and the Internet. It is known as: Network
1059 Server, Serving GW or Service Center.
1061 o LPWAN-AAA Server, which controls the user authentication, the
1062 applications. It is known as: Join-Server, Home Subscriber Server
1063 or Registration Authority. (We use the term LPWAN-AAA server
1064 because we're not assuming that this entity speaks RADIUS or
1065 Diameter as many/most AAA servers do, but equally we don't want to
1066 rule that out, as the functionality will be similar.
1068 o At last we have the Application Server, known also as Packet Data
1069 Node Gateway or Network Application.
1071 +---------------------------------------------------------------------+
1072 | Function/ | | | | |
1073 | Technology | LORAWAN | NB-IOT | SIGFOX | IETF |
1074 +--------------+-----------+------------+-------------+---------------+
1075 | Sensor, | | | | |
1076 | Actuator, | End | User | End | Device |
1077 |device, object| Device | Equipment | Point | (Dev) |
1078 +--------------+-----------+------------+-------------+---------------+
1079 | Transceiver | | Evolved | Base | RADIO |
1080 | Antenna | Gateway | Node B | Station | GATEWAY |
1081 +--------------+-----------+------------+-------------+---------------+
1082 | Server | Network | PDN GW/ | Service |Network Gateway|
1083 | | Server | SCEF | Center | (NGW) |
1084 +--------------+-----------+------------+-------------+---------------+
1085 | Security | Join | Home |Registration | LPWAN- |
1086 | Server | Server | Subscriber | Authority | AAA |
1087 | | | Server | | SERVER |
1088 +--------------+-----------+------------+-------------+---------------+
1089 | Application |Application| Application| Network | APPLICATION |
1090 | | Server | Server | Application | (App) |
1091 +---------------------------------------------------------------------+
1093 Figure 8: LPWAN Architecture Terminology
1095 +------+
1096 () () () | |LPWAN-|
1097 () () () () / \ +---------+ | AAA |
1098 () () () () () () / \========| /\ |====|Server| +-----------+
1099 () () () | | <--|--> | +------+ |APPLICATION|
1100 () () () () / \============| v |==============| (App) |
1101 () () () / \ +---------+ +-----------+
1102 Dev Radio Gateways NGW
1104 Figure 9: LPWAN Architecture
1106 In addition to the names of entities, LPWANs are also subject to
1107 possibly regional frequency band regulations. Those may include
1108 restrictions on the duty-cycle, for example requiring that hosts only
1109 transmit for a certain percentage of each hour.
1111 4. Gap Analysis
1113 4.1. Naive application of IPv6
1115 IPv6 [RFC2460] has been designed to allocate addresses to all the
1116 nodes connected to the Internet. Nevertheless, the header overhead
1117 of at least 40 bytes introduced by the protocol is incompatible with
1118 LPWAN constraints. If IPv6 with no further optimization were used,
1119 several LPWAN frames could be needed just to carry the IP header.
1120 Another problem arises from IPv6 MTU requirements, which require the
1121 layer below to support at least 1280 byte packets [RFC2460].
1123 IPv6 has a configuration protocol - neighbor discovery protocol,
1124 (NDP) [RFC4861]). For a node to learn network parameters NDP
1125 generates regular traffic with a relatively large message size that
1126 does not fit LPWAN constraints.
1128 In some LPWAN technologies, layer two multicast is not supported. In
1129 that case, if the network topology is a star, the solution and
1130 considerations of section 3.2.5 of [RFC7668] may be applied.
1132 Other key protocols such as DHCPv6 [RFC3315], IPsec [RFC4301] and TLS
1133 [RFC5246] have similarly problematic properties in this context.
1134 Each of those require relatively frequent round-trips between the
1135 host and some other host on the network. In the case of
1136 cryptographic protocols such as IPsec and TLS, in addition to the
1137 round-trips required for secure session establishment, cryptographic
1138 operations can require padding and addition of authenticators that
1139 are problematic when considering LPWAN lower layers.
1141 4.2. 6LoWPAN
1143 Several technologies that exhibit significant constraints in various
1144 dimensions have exploited the 6LoWPAN suite of specifications
1145 [RFC4944], [RFC6282], [RFC6775] to support IPv6 [I-D.hong-6lo-use-
1146 cases]. However, the constraints of LPWANs, often more extreme than
1147 those typical of technologies that have (re)used 6LoWPAN, constitute
1148 a challenge for the 6LoWPAN suite in order to enable IPv6 over LPWAN.
1149 LPWANs are characterized by device constraints (in terms of
1150 processing capacity, memory, and energy availability), and specially,
1151 link constraints, such as:
1153 o very low layer two payload size (from ~10 to ~100 bytes),
1155 o very low bit rate (from ~10 bit/s to ~100 kbit/s), and
1157 o in some specific technologies, further message rate constraints
1158 (e.g. between ~0.1 message/minute and ~1 message/minute) due to
1159 regional regulations that limit the duty cycle.
1161 4.2.1. Header Compression
1163 6LoWPAN header compression reduces IPv6 (and UDP) header overhead by
1164 eliding header fields when they can be derived from the link layer,
1165 and by assuming that some of the header fields will frequently carry
1166 expected values. 6LoWPAN provides both stateless and stateful header
1167 compression. In the latter, all nodes of a 6LoWPAN are assumed to
1168 share compression context. In the best case, the IPv6 header for
1169 link-local communication can be reduced to only 2 bytes. For global
1170 communication, the IPv6 header may be compressed down to 3 bytes in
1171 the most extreme case. However, in more practical situations, the
1172 smallest IPv6 header size may be 11 bytes (one address prefix
1173 compressed) or 19 bytes (both source and destination prefixes
1174 compressed). These headers are large considering the link layer
1175 payload size of LPWAN technologies, and in some cases are even bigger
1176 than the LPWAN PDUs. 6LoWPAN has been initially designed for IEEE
1177 802.15.4 networks with a frame size up to 127 bytes and a throughput
1178 of up to 250 kb/s, which may or may not be duty-cycled.
1180 4.2.2. Address Autoconfiguration
1182 Traditionally, Interface Identifiers (IIDs) have been derived from
1183 link layer identifiers [RFC4944] . This allows optimizations such as
1184 header compression. Nevertheless, recent guidance has given advice
1185 on the fact that, due to privacy concerns, 6LoWPAN devices should not
1186 be configured to embed their link layer addresses in the IID by
1187 default.
1189 4.2.3. Fragmentation
1191 As stated above, IPv6 requires the layer below to support an MTU of
1192 1280 bytes [RFC2460]. Therefore, given the low maximum payload size
1193 of LPWAN technologies, fragmentation is needed.
1195 If a layer of an LPWAN technology supports fragmentation, proper
1196 analysis has to be carried out to decide whether the fragmentation
1197 functionality provided by the lower layer or fragmentation at the
1198 adaptation layer should be used. Otherwise, fragmentation
1199 functionality shall be used at the adaptation layer.
1201 6LoWPAN defined a fragmentation mechanism and a fragmentation header
1202 to support the transmission of IPv6 packets over IEEE 802.15.4
1203 networks [RFC4944]. While the 6LoWPAN fragmentation header is
1204 appropriate for IEEE 802.15.4-2003 (which has a frame payload size of
1205 81-102 bytes), it is not suitable for several LPWAN technologies,
1206 many of which have a maximum payload size that is one order of
1207 magnitude below that of IEEE 802.15.4-2003. The overhead of the
1208 6LoWPAN fragmentation header is high, considering the reduced payload
1209 size of LPWAN technologies and the limited energy availability of the
1210 devices using such technologies. Furthermore, its datagram offset
1211 field is expressed in increments of eight octets. In some LPWAN
1212 technologies, the 6LoWPAN fragmentation header plus eight octets from
1213 the original datagram exceeds the available space in the layer two
1214 payload. In addition, the MTU in the LPWAN networks could be
1215 variable which implies a variable fragmentation solution.
1217 4.2.4. Neighbor Discovery
1219 6LoWPAN Neighbor Discovery [RFC6775] defined optimizations to IPv6
1220 Neighbor Discovery [RFC4861], in order to adapt functionality of the
1221 latter for networks of devices using IEEE 802.15.4 or similar
1222 technologies. The optimizations comprise host-initiated interactions
1223 to allow for sleeping hosts, replacement of multicast-based address
1224 resolution for hosts by an address registration mechanism, multihop
1225 extensions for prefix distribution and duplicate address detection
1226 (note that these are not needed in a star topology network), and
1227 support for 6LoWPAN header compression.
1229 6LoWPAN Neighbor Discovery may be used in not so severely constrained
1230 LPWAN networks. The relative overhead incurred will depend on the
1231 LPWAN technology used (and on its configuration, if appropriate). In
1232 certain LPWAN setups (with a maximum payload size above ~60 bytes,
1233 and duty-cycle-free or equivalent operation), an RS/RA/NS/NA exchange
1234 may be completed in a few seconds, without incurring packet
1235 fragmentation.
1237 In other LPWANs (with a maximum payload size of ~10 bytes, and a
1238 message rate of ~0.1 message/minute), the same exchange may take
1239 hours or even days, leading to severe fragmentation and consuming a
1240 significant amount of the available network resources. 6LoWPAN
1241 Neighbor Discovery behavior may be tuned through the use of
1242 appropriate values for the default Router Lifetime, the Valid
1243 Lifetime in the PIOs, and the Valid Lifetime in the 6CO, as well as
1244 the address Registration Lifetime. However, for the latter LPWANs
1245 mentioned above, 6LoWPAN Neighbor Discovery is not suitable.
1247 4.3. 6lo
1249 The 6lo WG has been reusing and adapting 6LoWPAN to enable IPv6
1250 support over link layer technologies such as Bluetooth Low Energy
1251 (BTLE), ITU-T G.9959, DECT-ULE, MS/TP-RS485, NFC IEEE 802.11ah. (See
1252 for details.) These technologies are
1253 similar in several aspects to IEEE 802.15.4, which was the original
1254 6LoWPAN target technology.
1256 6lo has mostly used the subset of 6LoWPAN techniques best suited for
1257 each lower layer technology, and has provided additional
1258 optimizations for technologies where the star topology is used, such
1259 as BTLE or DECT-ULE.
1261 The main constraint in these networks comes from the nature of the
1262 devices (constrained devices), whereas in LPWANs it is the network
1263 itself that imposes the most stringent constraints.
1265 4.4. 6tisch
1267 The 6tisch solution is dedicated to mesh networks that operate using
1268 802.15.4e MAC with a deterministic slotted channel. The time slot
1269 channel (TSCH) can help to reduce collisions and to enable a better
1270 balance over the channels. It improves the battery life by avoiding
1271 the idle listening time for the return channel.
1273 A key element of 6tisch is the use of synchronization to enable
1274 determinism. TSCH and 6TiSCH may provide a standard scheduling
1275 function. The LPWAN networks probably will not support
1276 synchronization like the one used in 6tisch.
1278 4.5. RoHC
1280 Robust header compression (RoHC) is a header compression mechanism
1281 [RFC3095] developed for multimedia flows in a point to point channel.
1282 RoHC uses 3 levels of compression, each level having its own header
1283 format. In the first level, RoHC sends 52 bytes of header, in the
1284 second level the header could be from 34 to 15 bytes and in the third
1285 level header size could be from 7 to 2 bytes. The level of
1286 compression is managed by a sequence number, which varies in size
1287 from 2 bytes to 4 bits in the minimal compression. SN compression is
1288 done with an algorithm called W-LSB (Window- Least Significant Bits).
1289 This window has a 4-bit size representing 15 packets, so every 15
1290 packets RoHC needs to slide the window in order to receive the
1291 correct sequence number, and sliding the window implies a reduction
1292 of the level of compression. When packets are lost or errored, the
1293 decompressor loses context and drops packets until a bigger header is
1294 sent with more complete information. To estimate the performance of
1295 RoHC, an average header size is used. This average depends on the
1296 transmission conditions, but most of the time is between 3 and 4
1297 bytes.
1299 RoHC has not been adapted specifically to the constrained hosts and
1300 networks of LPWANs: it does not take into account energy limitations
1301 nor the transmission rate, and RoHC context is synchronised during
1302 transmission, which does not allow better compression.
1304 4.6. ROLL
1306 Most technologies considered by the lpwan WG are based on a star
1307 topology, which eliminates the need for routing at that layer.
1308 Future work may address additional use-cases that may require
1309 adaptation of existing routing protocols or the definition of new
1310 ones. As of the time of writing, work similar to that done in the
1311 ROLL WG and other routing protocols are out of scope of the LPWAN WG.
1313 4.7. CoAP
1315 CoAP [RFC7252] provides a RESTful framework for applications intended
1316 to run on constrained IP networks. It may be necessary to adapt CoAP
1317 or related protocols to take into account for the extreme duty cycles
1318 and the potentially extremely limited throughput of LPWANs.
1320 For example, some of the timers in CoAP may need to be redefined.
1321 Taking into account CoAP acknowledgments may allow the reduction of
1322 L2 acknowledgments. On the other hand, the current work in progress
1323 in the CoRE WG where the COMI/CoOL network management interface
1324 which, uses Structured Identifiers (SID) to reduce payload size over
1325 CoAP may prove to be a good solution for the LPWAN technologies. The
1326 overhead is reduced by adding a dictionary which matches a URI to a
1327 small identifier and a compact mapping of the YANG model into the
1328 CBOR binary representation.
1330 4.8. Mobility
1332 LPWANs nodes can be mobile. However, LPWAN mobility is different
1333 from the one specified for Mobile IP. LPWAN implies sporadic traffic
1334 and will rarely be used for high-frequency, real-time communications.
1335 The applications do not generate a flow, they need to save energy and
1336 most of the time the node will be down.
1338 In addition, LPWAN mobility may mostly apply to groups of devices,
1339 that represent a network in which case mobility is more a concern for
1340 the gateway than the devices. NEMO [RFC3963] Mobility solutions may
1341 be used in the case where some end-devices belonging to the same
1342 network gateway move from one point to another such that they are not
1343 aware of being mobile.
1345 4.9. DNS and LPWAN
1347 The Domain Name System (DNS) DNS [RFC1035], enables applications to
1348 name things with a globally resolvable name. Many protocols use the
1349 DNS to identify hosts, for example applications using CoAP.
1351 The DNS query/answer protocol as a pre-cursor to other communication
1352 within the time-to-live (TTL) of a DNS answer is clearly problematic
1353 in an LPWAN, say where only one round-trip per hour can be used, and
1354 with a TTL that is less than 3600. It is currently unclear whether
1355 and how DNS-like functionality might be provided in LPWANs.
1357 5. Security Considerations
1359 Most LPWAN technologies integrate some authentication or encryption
1360 mechanisms that were defined outside the IETF. The working group may
1361 need to do work to integrate these mechanisms to unify management. A
1362 standardized Authentication, Accounting, and Authorization (AAA)
1363 infrastructure [RFC2904] may offer a scalable solution for some of
1364 the security and management issues for LPWANs. AAA offers
1365 centralized management that may be of use in LPWANs, for example
1366 [I-D.garcia-dime-diameter-lorawan] and
1367 [I-D.garcia-radext-radius-lorawan] suggest possible security
1368 processes for a LoRaWAN network. Similar mechanisms may be useful to
1369 explore for other LPWAN technologies.
1371 Some applications using LPWANs may raise few or no privacy
1372 considerations. For example, temperature sensors in a large office
1373 building may not raise privacy issues. However, the same sensors, if
1374 deployed in a home environment and especially if triggered due to
1375 human presence, can raise significant privacy issues - if an end-
1376 device emits (an encrypted) packet every time someone enters a room
1377 in a home, then that traffic is privacy sensitive. And the more that
1378 the existence of that traffic is visible to network entities, the
1379 more privacy sensitivities arise. At this point, it is not clear
1380 whether there are workable mitigations for problems like this - in a
1381 more typical network, one would consider defining padding mechanisms
1382 and allowing for cover traffic. In some LPWANs, those mechanisms may
1383 not be feasible. Nonetheless, the privacy challenges do exist and
1384 can be real and so some solutions will be needed. Note that many
1385 aspects of solutions in this space may not be visible in IETF
1386 specifications, but can be e.g. implementation or deployment
1387 specific.
1389 Another challenge for LPWANs will be how to handle key management and
1390 associated protocols. In a more traditional network (e.g. the web),
1391 servers can "staple" OCSP responses in order to allow browsers to
1392 check revocation status for presented certificates. [RFC6961] While
1393 the stapling approach is likely something that would help in an
1394 LPWAN, as it avoids an RTT, certificates and OCSP responses are bulky
1395 items and will prove challenging to handle in LPWANs with bounded
1396 bandwidth.
1398 6. IANA Considerations
1400 There are no IANA considerations related to this memo.
1402 7. Contributors
1404 As stated above this document is mainly a collection of content
1405 developed by the full set of contributors listed below. The main
1406 input documents and their authors were:
1408 o Text for Section 2.1 was provided by Alper Yegin and Stephen
1409 Farrell in [I-D.farrell-lpwan-lora-overview].
1411 o Text for Section 2.2 was provided by Antti Ratilainen in
1412 [I-D.ratilainen-lpwan-nb-iot].
1414 o Text for Section 2.3 was provided by Juan Carlos Zuniga and Benoit
1415 Ponsard in [I-D.zuniga-lpwan-sigfox-system-description].
1417 o Text for Section 2.4 was provided via personal communication from
1418 Bob Heile (bheile@ieee.org) and was authored by Bob and Sum Chin
1419 Sean. There is no Internet draft for that at present.
1421 o Text for Section 4 was provided by Ana Minabiru, Carles Gomez,
1422 Laurent Toutain, Josep Paradells and Jon Crowcroft in
1423 [I-D.minaburo-lpwan-gap-analysis]. Additional text from that
1424 draft is also used elsewhere above.
1426 The full list of contributors are:
1428 Jon Crowcroft
1429 University of Cambridge
1430 JJ Thomson Avenue
1431 Cambridge, CB3 0FD
1432 United Kingdom
1434 Email: jon.crowcroft@cl.cam.ac.uk
1436 Carles Gomez
1437 UPC/i2CAT
1438 C/Esteve Terradas, 7
1439 Castelldefels 08860
1440 Spain
1442 Email: carlesgo@entel.upc.edu
1444 Bob Heile
1445 Wi-Sun Alliance
1446 11 Robert Toner Blvd, Suite 5-301
1447 North Attleboro, MA 02763
1448 USA
1450 Phone: +1-781-929-4832
1451 Email: bheile@ieee.org
1453 Ana Minaburo
1454 Acklio
1455 2bis rue de la Chataigneraie
1456 35510 Cesson-Sevigne Cedex
1457 France
1459 Email: ana@ackl.io
1461 Josep PAradells
1462 UPC/i2CAT
1463 C/Jordi Girona, 1-3
1464 Barcelona 08034
1465 Spain
1467 Email: josep.paradells@entel.upc.edu
1469 Benoit Ponsard
1470 SIGFOX
1471 425 rue Jean Rostand
1472 Labege 31670
1473 France
1475 Email: Benoit.Ponsard@sigfox.com
1476 URI: http://www.sigfox.com/
1478 Antti Ratilainen
1479 Ericsson
1480 Hirsalantie 11
1481 Jorvas 02420
1482 Finland
1484 Email: antti.ratilainen@ericsson.com
1486 Chin-Sean SUM
1487 Wi-Sun Alliance
1488 20, Science Park Rd
1489 Singapore 117674
1490 Phone: +65 6771 1011
1491 Email: sum@wi-sun.org
1493 Laurent Toutain
1494 Institut MINES TELECOM ; TELECOM Bretagne
1495 2 rue de la Chataigneraie
1496 CS 17607
1497 35576 Cesson-Sevigne Cedex
1498 France
1500 Email: Laurent.Toutain@telecom-bretagne.eu
1502 Alper Yegin
1503 Actility
1504 Paris, Paris
1505 FR
1507 Email: alper.yegin@actility.com
1509 Juan Carlos Zuniga
1510 SIGFOX
1511 425 rue Jean Rostand
1512 Labege 31670
1513 France
1515 Email: JuanCarlos.Zuniga@sigfox.com
1516 URI: http://www.sigfox.com/
1518 8. Acknowledgments
1520 Thanks to all those listed in Section 7 for the excellent text.
1521 Errors in the handling of that are solely the editor's fault.
1523 In addition to the contributors above, thanks are due to Arun
1524 (arun@acklio.com), Dan Garcia Carrillo, Paul Duffy, Thad Guidry,
1525 Jiazi Yi, for comments.
1527 [[Ed: If I omitted anyone, sorry and just let me know and I'll add
1528 you here.]]
1530 Alexander Pelov and Pascal Thubert were the LPWAN WG chairs while
1531 this document was developed.
1533 Stephen Farrell's work on this memo was supported by the Science
1534 Foundation Ireland funded CONNECT centre .
1536 9. Informative References
1538 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
1539 DOI 10.17487/RFC0768, August 1980,
1540 .
1542 [RFC1035] Mockapetris, P., "Domain names - implementation and
1543 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
1544 November 1987, .
1546 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
1547 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
1548 December 1998, .
1550 [RFC2904] Vollbrecht, J., Calhoun, P., Farrell, S., Gommans, L.,
1551 Gross, G., de Bruijn, B., de Laat, C., Holdrege, M., and
1552 D. Spence, "AAA Authorization Framework", RFC 2904,
1553 DOI 10.17487/RFC2904, August 2000,
1554 .
1556 [RFC3095] Bormann, C., Burmeister, C., Degermark, M., Fukushima, H.,
1557 Hannu, H., Jonsson, L-E., Hakenberg, R., Koren, T., Le,
1558 K., Liu, Z., Martensson, A., Miyazaki, A., Svanbro, K.,
1559 Wiebke, T., Yoshimura, T., and H. Zheng, "RObust Header
1560 Compression (ROHC): Framework and four profiles: RTP, UDP,
1561 ESP, and uncompressed", RFC 3095, DOI 10.17487/RFC3095,
1562 July 2001, .
1564 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
1565 C., and M. Carney, "Dynamic Host Configuration Protocol
1566 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
1567 2003, .
1569 [RFC3963] Devarapalli, V., Wakikawa, R., Petrescu, A., and P.
1570 Thubert, "Network Mobility (NEMO) Basic Support Protocol",
1571 RFC 3963, DOI 10.17487/RFC3963, January 2005,
1572 .
1574 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the
1575 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
1576 December 2005, .
1578 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
1579 Control Message Protocol (ICMPv6) for the Internet
1580 Protocol Version 6 (IPv6) Specification", RFC 4443,
1581 DOI 10.17487/RFC4443, March 2006,
1582 .
1584 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
1585 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
1586 DOI 10.17487/RFC4861, September 2007,
1587 .
1589 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
1590 "Transmission of IPv6 Packets over IEEE 802.15.4
1591 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
1592 .
1594 [RFC5216] Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS
1595 Authentication Protocol", RFC 5216, DOI 10.17487/RFC5216,
1596 March 2008, .
1598 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
1599 (TLS) Protocol Version 1.2", RFC 5246,
1600 DOI 10.17487/RFC5246, August 2008,
1601 .
1603 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
1604 Housley, R., and W. Polk, "Internet X.509 Public Key
1605 Infrastructure Certificate and Certificate Revocation List
1606 (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
1607 .
1609 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
1610 Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
1611 DOI 10.17487/RFC6282, September 2011,
1612 .
1614 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
1615 Bormann, "Neighbor Discovery Optimization for IPv6 over
1616 Low-Power Wireless Personal Area Networks (6LoWPANs)",
1617 RFC 6775, DOI 10.17487/RFC6775, November 2012,
1618 .
1620 [RFC6961] Pettersen, Y., "The Transport Layer Security (TLS)
1621 Multiple Certificate Status Request Extension", RFC 6961,
1622 DOI 10.17487/RFC6961, June 2013,
1623 .
1625 [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
1626 Application Protocol (CoAP)", RFC 7252,
1627 DOI 10.17487/RFC7252, June 2014,
1628 .
1630 [RFC7668] Nieminen, J., Savolainen, T., Isomaki, M., Patil, B.,
1631 Shelby, Z., and C. Gomez, "IPv6 over BLUETOOTH(R) Low
1632 Energy", RFC 7668, DOI 10.17487/RFC7668, October 2015,
1633 .
1635 [I-D.farrell-lpwan-lora-overview]
1636 Farrell, S. and A. Yegin, "LoRaWAN Overview", draft-
1637 farrell-lpwan-lora-overview-01 (work in progress), October
1638 2016.
1640 [I-D.minaburo-lpwan-gap-analysis]
1641 Minaburo, A., Gomez, C., Toutain, L., Paradells, J., and
1642 J. Crowcroft, "LPWAN Survey and GAP Analysis", draft-
1643 minaburo-lpwan-gap-analysis-02 (work in progress), October
1644 2016.
1646 [I-D.zuniga-lpwan-sigfox-system-description]
1647 Zuniga, J. and B. PONSARD, "SIGFOX System Description",
1648 draft-zuniga-lpwan-sigfox-system-description-02 (work in
1649 progress), March 2017.
1651 [I-D.ratilainen-lpwan-nb-iot]
1652 Ratilainen, A., "NB-IoT characteristics", draft-
1653 ratilainen-lpwan-nb-iot-00 (work in progress), July 2016.
1655 [I-D.garcia-dime-diameter-lorawan]
1656 Garcia, D., Lopez, R., Kandasamy, A., and A. Pelov,
1657 "LoRaWAN Authentication in Diameter", draft-garcia-dime-
1658 diameter-lorawan-00 (work in progress), May 2016.
1660 [I-D.garcia-radext-radius-lorawan]
1661 Garcia, D., Lopez, R., Kandasamy, A., and A. Pelov,
1662 "LoRaWAN Authentication in RADIUS", draft-garcia-radext-
1663 radius-lorawan-03 (work in progress), May 2017.
1665 [TGPP36300]
1666 3GPP, "TS 36.300 v13.4.0 Evolved Universal Terrestrial
1667 Radio Access (E-UTRA) and Evolved Universal Terrestrial
1668 Radio Access Network (E-UTRAN); Overall description; Stage
1669 2", 2016,
1670 .
1672 [TGPP36321]
1673 3GPP, "TS 36.321 v13.2.0 Evolved Universal Terrestrial
1674 Radio Access (E-UTRA); Medium Access Control (MAC)
1675 protocol specification", 2016.
1677 [TGPP36322]
1678 3GPP, "TS 36.322 v13.2.0 Evolved Universal Terrestrial
1679 Radio Access (E-UTRA); Radio Link Control (RLC) protocol
1680 specification", 2016.
1682 [TGPP36323]
1683 3GPP, "TS 36.323 v13.2.0 Evolved Universal Terrestrial
1684 Radio Access (E-UTRA); Packet Data Convergence Protocol
1685 (PDCP) specification (Not yet available)", 2016.
1687 [TGPP36331]
1688 3GPP, "TS 36.331 v13.2.0 Evolved Universal Terrestrial
1689 Radio Access (E-UTRA); Radio Resource Control (RRC);
1690 Protocol specification", 2016.
1692 [TGPP36201]
1693 3GPP, "TS 36.201 v13.2.0 - Evolved Universal Terrestrial
1694 Radio Access (E-UTRA); LTE physical layer; General
1695 description", 2016.
1697 [TGPP23720]
1698 3GPP, "TR 23.720 v13.0.0 - Study on architecture
1699 enhancements for Cellular Internet of Things", 2016.
1701 [TGPP33203]
1702 3GPP, "TS 33.203 v13.1.0 - 3G security; Access security
1703 for IP-based services", 2016.
1705 [fcc_ref] "FCC CFR 47 Part 15.247 Telecommunication Radio Frequency
1706 Devices - Operation within the bands 902-928 MHz,
1707 2400-2483.5 MHz, and 5725-5850 MHz.", June 2016.
1709 [etsi_ref]
1710 "ETSI EN 300-220 (Parts 1 and 2): Electromagnetic
1711 compatibility and Radio spectrum Matters (ERM); Short
1712 Range Devices (SRD); Radio equipment to be used in the 25
1713 MHz to 1 000 MHz frequency range with power levels ranging
1714 up to 500 mW", May 2016.
1716 [arib_ref]
1717 "ARIB STD-T108 (Version 1.0): 920MHz-Band Telemeter,
1718 Telecontrol and data transmission radio equipment.",
1719 February 2012.
1721 [LoRaSpec]
1722 LoRa Alliance, "LoRaWAN Specification Version V1.0.2",
1723 July 2016, .
1727 [LoRaSpec1.0]
1728 LoRa Alliance, "LoRaWAN Specification Version V1.0", Jan
1729 2015, .
1732 [ANSI-4957-000]
1733 ANSI, TIA-4957.000, "Architecture Overview for the Smart
1734 Utility Network", May 2013, .
1737 [ANSI-4957-210]
1738 ANSI, TIA-4957.210, "Multi-Hop Delivery Specification of a
1739 Data Link Sub-Layer", May 2013, .
1742 [wisun-pressie1]
1743 Phil Beecher, Chair, Wi-SUN Alliance, "Wi-SUN Alliance
1744 Overview", March 2017, .
1748 [wisun-pressie2]
1749 Bob Heile, Director of Standards, Wi-SUN Alliance, "IETF97
1750 Wi-SUN Alliance Field Area Network (FAN) Overview",
1751 November 2016,
1752 .
1755 [IEEE-802-15-4]
1756 "IEEE Standard for Low-Rate Wireless Personal Area
1757 Networks (WPANs)", IEEE Standard 802.15.4, 2015,
1758 .
1761 [IEEE-802-15-9]
1762 "IEEE Recommended Practice for Transport of Key Management
1763 Protocol (KMP) Datagrams", IEEE Standard 802.15.9, 2016,
1764 .
1767 [etsi_unb]
1768 "ETSI TR 103 435 System Reference document (SRdoc); Short
1769 Range Devices (SRD); Technical characteristics for Ultra
1770 Narrow Band (UNB) SRDs operating in the UHF spectrum below
1771 1 GHz", February 2017.
1773 Appendix A. Changes
1775 A.1. From -00 to -01
1777 o WG have stated they want this to be an RFC.
1779 o WG clearly want to keep the RF details.
1781 o Various changes made to remove/resolve a number of editorial notes
1782 from -00 (in some cases as per suggestions from Ana Minaburo)
1784 o Merged PR's: #1...
1786 o Rejected PR's: #2 (change was made to .txt not .xml but was
1787 replicated manually by editor)
1789 o Github repo is at: https://github.com/sftcd/lpwan-ov
1791 A.2. From -01 to -02
1793 o WG seem to agree with editor suggestions in slides 13-24 of the
1794 presentation on this topic given at IETF98 (See:
1795 https://www.ietf.org/proceedings/98/slides/slides-98-lpwan-
1796 aggregated-slides-07.pdf)
1798 o Got new text wrt Wi-SUN via email from Paul Duffy and merged that
1799 in
1801 o Reflected list discussion wrt terminology and "end-device"
1803 o Merged PR's: #3...
1805 A.3. From -02 to -03
1807 o Editorial changes and typo fixes thanks to Fred Baker running
1808 something called Grammerly and sending me it's report.
1810 o Merged PR's: #4, #6, #7...
1812 o Editor did an editing pass on the lot.
1814 A.4. From -03 to -04
1816 o Picked up a PR that had been wrongly applied that expands UE
1818 o Editorial changes wrt LoRa suggested by Alper
1820 o Editorial changes wrt SIGFOX provided by Juan-Carlos
1822 Author's Address
1824 Stephen Farrell (editor)
1825 Trinity College Dublin
1826 Dublin 2
1827 Ireland
1829 Phone: +353-1-896-2354
1830 Email: stephen.farrell@cs.tcd.ie